1. Technical Field
The present disclosure relates to an illuminance detecting component and an illuminance detecting apparatus and, more particularly, to an illuminance detecting component and an illuminance detecting apparatus for detecting an illuminance of light irradiated from the outside.
2. Background Art
In the related art, in manufacturing a wiring substrate such as a printed board, as shown in FIG. 1, an exposure apparatus 100 having a Digital Micromirror Device (DMD) 106 is used for exposing a resist film or a film-like resist.
FIG. 1 is a schematic view of an exposure apparatus used in manufacturing a wiring substrate. Also, in FIG. 1, the exposure apparatus 100 can expose to light at a time in an area J (referred to as a “light irradiation area J” hereinafter), and K denotes a scanning direction of light (referred to as a “K direction” hereinafter).
By reference to FIG. 1, the exposure apparatus 100 includes a stage 101, a light source 105, the Digital Micromirror Device (DMD) 106, a light absorbing plate 107, and a projection lens 108.
The stage 101 is provided to fix a wiring substrate 102 on which a resist film 103 is formed. The light source 105 is disposed on the obliquely lower side of the DMD 106. The light source 105 is provided which radiates light onto the DMD 106.
The DMD 106 is provided over the stage 101 to face the wiring substrate 102. The DMD 106 has a plurality of micromirrors to receive the light emitted from the light source 105. When data (electric signal) corresponding to the pattern to be exposed is input, the DMD 106 tilts the micromirrors in response to the data to reflect the light emitted from the light source 105 to the resist film 103 and expose the resist film 103.
The light absorbing plate 107 is disposed on the obliquely lower side of the DMD 106. The light absorbing plate 107 is provided which absorbs the reflected light unnecessary for the exposure. The projection lens 108 is disposed between the DMD 106 and the wiring substrate 102. The projection lens 108 is provided which adjusts a light traveling direction, the light irradiation area J, and the like.
When exposure process of the resist film 103 is performed using the exposure apparatus 100 constructed as above, it is important to recognize an illuminance distribution of light in a plane of the wiring substrate 102 when the resist film 103 is patterned into a desired shape after the development process.
As the illuminance detecting apparatus for detecting an illuminance of light in a plane of the wiring substrate 102 in the related art, there is an illuminance detecting apparatus 112 shown in FIG. 2.
FIG. 2 is a view describing an illuminance detecting apparatus in the related art, and FIG. 3 is an enlarged sectional view of the illuminance detecting apparatus shown in FIG. 2. In FIG. 2, such a situation is schematically illustrated that the illuminance detecting apparatus 112 detects an illuminance of light irradiated from the exposure apparatus 100. Also, the illustration of wiring patterns 116, 117 shown in FIG. 3 will be omitted from FIG. 2. In FIG. 3, PA denotes an alignment pitch of photo diodes 122 (referred to as an “alignment pitch PA” hereinafter) when a plurality of illuminance detecting units 114 are disposed at a predetermined interval.
By reference to FIG. 2, the illuminance detecting apparatus 112 in the related art includes an aligning plate 113 and a plurality of illuminance detecting units 114.
By reference to FIGS. 2 and 3, the aligning plate 113 is provided which aligns a plurality of illuminance detecting units 114 thereon and has a plate 115 and the wiring patterns 116, 117. The wiring patterns 116, 117 are formed on an upper surface 115A of the plate 115. The wiring patterns 116, 117 are connected electrically to the illuminance detecting units 114. The wiring patterns 116, 117 are wirings that lead detection signals that the illuminance detecting units 114 detect and also supply an electric power to the illuminance detecting units 114.
Each of the illuminance detecting units 114 includes a ceramic substrate 121, the photo diode 122, a ceramic frame 124, a glass substrate 126, and leads 128, 129. The plurality of illuminance detecting units 114 are disposed on the aligning plate 113 such that the photo diodes 122 are disposed at an alignment pitch PA. The ceramic substrate 121 has a ceramic substrate body 131 and pads 133, 134. The pads 133, 134 are provided on an upper surface 131A of the ceramic substrate body 131.
The photo diode 122 is provided on the pad 134. The photo diode 122 has a positive electrode 136 and a light receiving portion 138 on its upper surface side, and has a negative electrode 137 on its lower surface side. The positive electrode 136 is connected electrically to the pad 133 via a wire 125. The light receiving portion 138 is provided to receive light which is reflected from the DMD 106 and then passes through the projection lens 108. The negative electrode 137 is disposed on the pad 134, and is connected electrically to the pad 134.
The ceramic frame 124 has a through hole 124A in which the photo diode 122 is accommodated. The ceramic frame 124 is provided on the pads 133, 134 and the upper surface 131A of the ceramic substrate body 131 so as to surround the photo diode 122.
The ceramic substrate 121 and the ceramic frame 124 as described above are formed by laminating a second green sheet in which the through hole 124A is formed (this green sheet constitutes the ceramic frame 124 after the sintering) on a first green sheet on which conductors acting as the pads 133, 134 are formed (this green sheet constitutes the ceramic substrate 121 after the sintering), and then sintering them.
The glass substrate 126 is shaped like a plate, and is provided on the ceramic frame 124. The glass substrate 126 is provided to pass through the light irradiated from the exposure apparatus 100 and also to seal tightly a space L in which the photo diode 122 is accommodated.
The lead 128 is connected to a portion, which is positioned on the outside of the ceramic frame 124, of the pad 133. The lead 128 is the external connection terminal of the illuminance detecting unit 114, and is connected electrically to the wiring pattern 116 via a solder 141. Thus, the wiring pattern 116 is connected electrically to the positive electrode 136 of the photo diode 122.
The lead 129 is connected to a portion, which is positioned on the outside of the ceramic frame 124, of the pad 134. The lead 129 is the external connection terminal of the illuminance detecting unit 114, and is connected electrically to the wiring pattern 117 via a solder 142. Thus, the wiring pattern 117 is connected electrically to the negative electrode 137 of the photo diode 122 (see e.g., Japanese Patent Application Publication No. 2007-27279).
However, according to the illuminance detecting apparatus 112 in the related art, the plurality of illuminance detecting units 114 on which one photo diode 122 is provided respectively are disposed on the aligning plate 113, and therefore it is difficult to narrow the alignment pitch PA of the photo diodes 122. As a result, such a problem existed that a detailed distribution of an illuminance of light irradiated from the exposure apparatus 100 cannot be detected.